1. Field of the Invention
This invention relates in general to a supervisory system for controlling the operation of a vehicle in a transportation system and, in particular, to a programmable processor for controlling a vehicle by receiving service condition signals from the control system and generating control signals in response thereto to control the vehicle in accordance with a predetermined program.
2. Description of the Prior Art
In the discussion which follows, the transportation system of the invention will be disclosed as an elevator system in which the vehicle or vehicles of the system are elevator care, the station calls registered by prospective passengers will be elevator hall calls, the calls registered by passengers within the vehicle will be elevator car calls and the various other system functions will be discussed in elevator system parlance. However, it is to be understood that the invention is applicable to other transportation systems such as horizontally traveling cars or trains of cars for mass transit systems, the class of systems employing smaller vehicles identified as personal rapid transit systems, or conveyors as employed in warehousing and local distribution systems.
Heretofore, the operations of elevators have been controlled by combinations of switching elements having timing and storage functions which establish operating sequences according to various anticipated combinations of car position, call location, car speed, door conditions, car loading and safety conditions. The combinations of elements have been specifically constructed for the control to be achieved such that essentially custom equipment is assembled for each elevator system.
Even the relatively simple logic of a single car selective-collective elevator requires a substantial amount of circuitry to correlate operation of the car starting and stopping controls, direction controls and door controls with call registering devices in the car and at the landings, door protective devices and the various safety devices. Further, where logic circuitry is hard wired for such control functions, little or no flexibility in the operating patterns of the car is available at reasonable expense. The inflexibility of prior elevator systems becomes even more significant as the complexity of the systems increases.
A transportation system including a programmable computer controlled supervisor is disclosed in co-pending U.S. Pat. application Ser. No. 536,199, filed Dec. 24, 1974 in the name of Robert E. Senn et al. and entitled "Transportation System With Programmable Computer Controlled Supervisor", which is assigned to the same assignee as the present application. This system utilizes a general purpose computer with appropriate interfacing to the elevator hoist motor, call registering devices, car position sensors, door operators and safety devices whereby a wide latitude of logic functions is available in establishing the control and operating patterns of elevators. The computer includes a processor for performing the control logic for each car and a memory for storing data. A feature of the system is to maximize, within practical limits, the logic functions performed within the processor and as a corollary, to minimize the logic functions performed in the interface hardware between the system and the processor. One aspect of these features is the utilization of the computer memory in preference to the interface memory to thereby reduce the more expensive interface equipment and increase the speed of access by the processor to the data in the memory.
An elevator system utilizing a system processor to assign hall calls to a plurality of elevator cars is disclosed in U.S. Pat. No. 3,854,554, issued Dec. 17, 1974 to Clyde A. Booker, Jr. Each elevator car includes a car controller capable of directing the car to independently answer hall calls. The system processor controls the elevator cars by providing assignment signals for the car controllers of all the cars which override the normal operation of the car controllers and prevent selected hall calls from being considered by selected cars. Failure of the system processor to provide assignment signals automatically enables the car controllers of all of the cars to consider all of the hall calls. The system is implemented by a system processor which generates assignment signals to selected cars and generates a master assignment signal to all the cars representing all hall calls which have been assigned. The car controller for each car compares its assignment with the master assignment signal and provides inhibit signals for blocking those calls from consideration which are not assigned thereto.